1. Field of the Invention
The present invention relates to a pharmaceutical composition, and more specifically to a taste-masking oral dosage form and method of preparing the same.
2. Description of the Related Art
There are various types of oral administrative medicines, such as tablets, capsules, granules, powders, syrups and the like. Orally administrated medicines, however, suffer from many drawbacks. For example, pharmaceutically active ingredients in medicines may leave an unpleasant taste after drug administration.
Tablets and capsules, for example, may be hard to swallow for the elderly or children. Granules and powders may possibly enter the respiratory tract or lungs. Additionally, dosage of syrups, may be difficult measured, particularly for the elderly or children.
Therefore, many researches regarding taste-masking oral dosage forms have been undertaken recently to provide a new generation rapidly dissolved and safely swallowed tablets, and their dosages can be accurately measured, particularly can mask bitter. Additionally, tablets should possess adequate hardness to facilitate the packaging process.
Several related arts are disclosed in the following. U.S. Pat. No. 5,804,212 describes a preparation in which a starch and a nasal drug are blended to form a microparticle to improve nasal absorption. European Patent No. 230264 discloses an aqueous nasal drug delivery system for vaccines comprising a high molecular weight drug, a gelling agent such as hydroxyethyl cellulose, and additives such as surfactants or glycerol. The two examples (U.S. Pat. No. 5,804,212 and European Patent No. 230264) merely cite how to improve drug absorption effects, without commenting on taste-masking effects.
Japanese Patent Laid-open No. 76420/1977 and 24410/1983 describe a method of preparing a porous tablet which comprises blending a tablet-constituting composition with inert solvent, solidifying, compressing the resulting solid into tablets, and evaporating solvent by freeze-drying. U.S. Pat. No. 5,501,861 discloses a method of preparing a fast dissolving tablet comprising a water-soluble saccharide (such as sugar, starch, lactose, sugar alcohol, or tetrose) and a pharmacologically active ingredient, which comprises compressing the blended solid into tablets with a molding pressure of 5˜130 kg/cm2 and evaporating the solvent by freeze-drying.
The above fast dissolving tablets are prepared by Zydis (from R. P. Scherer, England) freeze-drying. This method, however, suffer from high process cost and insufficient mechanical strength of the preparation.
Therefore, it is necessary to develop a preparation which offers a pleasant taste and acceptable disintegration speed in an oral cavity after dosage, and possesses a sufficient mechanical strength so as to protect the preparation from destruction in the course of manufacture.